The present invention relates generally to rotary die cutting apparatus, and, more particularly, to rotary die cutting apparatus for forming computer readable punchout tabulation cards.
Punchout tabulation cards as those formed by the present invention are similar to normal computer tabulation cards, with the exception that the punchout cards include a pattern of substantially identical punchout areas that may be displaced from the card upon the application of pressure, i.e., being pressed on with a pencil point. Each punch, or punchout area, is typically formed as a substantially rectangular pattern cut through the thickness of the tabulation card. The cut, however, does not completely outline the punch area and is interrupted by short, uncut portions that serve as anchors to keep the punch in place until pressure is applied. After one or more of the punches has been displaced, the card is typically inserted into an optical data scanner, to interpret the information represented by displacement of the particular punch.
A number of devices have heretofore been used for cutting rolls of sheet paper to form computer readable tabulation cards. Those devices may also be operative to perform such functions as printing the desired material on the face of the sheet, cutting the sheet into cards, cutting or rounding corners of the cards, ejecting defective cards and stacking acceptable cards.
Contemporary mechanisms for punching hole patterns in tabulation cards utilize either rotary punch mechanisms or flat press mechanisms. The rotary punching mechanisms include a male rotary cutting die and a cooperating female or anvil roller. Contemporary die rollers for card punching operations are typically comprised of a pattern of adjustable die elements that can be extended a variable distance from the die roller outer surface. Contemporary anvil rollers for card punching operations are comprised of a similar pattern of elements that can be retracted inwardly from the outer surface of the anvil roller to receive the male counterpart on the die roller. Thus, tabulation cards passing between the die roller and anvil roller abut against the extending die roller elements and are urged against the cooperating anvil roller cavity until the card is punched and the punch withdrawn by a vacuum source connected to the interior of the anvil roller.
Such contemporary mechanisms are unsuitable for use in the formation of punchout cards, in that the area defined by the die cutting elements is totally removed from the card. Moreover, such mechanisms do not readily lend themselves to modification to form punchout cards. For example, the male die cutting elements for those contemporary mechanisms must be sufficiently small and short so as not to break off when the die cutting element engages the recesses in the rotating anvil roller. Additionally, because the upper surface of the die cutting elements is typically smooth and flat to permit the cutting element to be flush with the surface of the roller when the element is withdrawn, the die cutting elements do not cleanly cut through the tabulation card when the corresponding anvil element is disposed flush with the outer surface of the anvil roller. When the anvil element is withdrawn from the surface of the roller, the mechanism tends to completely separate the punched area from the card.
At present, mechanisms for fabricating punchout tabulation cards, known as portapunches, have been limited to flatbed presses. Though flatbed presses are adequate to properly form punchout areas on the tabulation cards, they operate too slowly, i.e., approximately 5,000 cards an hour. Accordingly, it has been difficult to use those presses to profitably manufacture punchout tabulation cards, in view of that limited production rate and the costs of the press mechanism.
Accordingly, it is a principal object of the present invention to provide a rotary mechanism for producing punchout tabulation cards that far exceeds the operating rate of similarly operative contemporary mechanisms.
It is also an object of the present invention to provide a rotary mechanism for producing punchout tabulation cards that can be readily modified to form different punchout patterns on the card by changing only one of the cooperating rollers.
It is a further object of the invention to provide a rotary mechanism for fabricating punchout tabulation cards wherein the movement of the rollers need not be synchronized.